Hitherto, a test apparatus provided with a probe card including a plurality of probes has been used when testing an electronic device such as a semiconductor device. In this case, an electronic device is fixed on a probe station of the test apparatus, a probe of the probe card is brought close to the probe station, and the tip of the probe is brought into contact with a terminal of the electronic device to be tested. In general, in testing an electronic device, a test for resistance properties of the electronic device to temperature changes is performed. Thus, methods for maintaining a correct position of a probe are disclosed.
For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 5-011018) describes a probe card. In the probe card, probes in each of which a curved portion is formed are fixed to a thin substrate, using insulating resin, and the probes are fixed by disposing a metal ring having a high thermal expansion coefficient inside the curved portions while insulating the probes by the use of insulating resin. In this arrangement, the probe card enables a heat test in a wide range of temperatures, using a single card, by changing the position of the tip of each of the probes in response to the temperature.
Moreover, Patent Document 2 (Japanese Unexamined Patent Application Publication No. 6-174746) describes a heat-resistant probe card. In the heat-resistant probe card, elastic members are set to intervene in a portion adhesively fixed between a probe card substrate to which the respective bases of probes are fixed and a fixing ring fixing the respective intermediate joints of the probes, and a flexible bending portion is provided between the base and intermediate joint of each of the probes. In this arrangement, when the heat-resistant probe card is used in a test mode with sharp temperature variations, the heat-resistant probe card prevents the positional shift of the tip of the probe due to a difference in the thermal expansion coefficient.
Moreover, Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2004-045285) describes a probe card. The probe card includes a substrate, a plurality of probes coming into contact with a plurality of terminals of an electronic device, and a plurality of signal lines. At least one of the probes is a bimorph pin including a first member that has a first thermal expansion coefficient and is disposed obliquely with respect to a surface of a terminal of a corresponding electronic device and a second member that has a second thermal expansion coefficient that is lower than the first thermal expansion coefficient and is joined to the first member. In this arrangement, the probe card can maintain satisfactory contact with an electronic device.
In general, a probe card to be used in a semiconductor wafer test is designed and manufactured so that the tip of a probe is positioned to the center of a chip pad of a large-scale integrated circuit (LSI) at a specified temperature. A probe is composed of, for example, tungsten having a low thermal expansion coefficient (thermal expansion coefficient: 4.5 ppm/K). As the size of an LSI is decreased, the size of a pad is also decreased. Thus, a change in the position of a probe due to thermal expansion cannot be disregarded.
FIG. 11 is a diagram showing a change in the position of the tip of a known probe due to thermal expansion. A probe card 10a shown in FIG. 11(a) includes a substrate 11 and a probe 12a. The tip of the probe 12a is bended in a hook shape, and the base of the probe 12a is joined to the substrate 11 by the use of a solder 14. In general, a fixation portion 111 of the probe card 10a is fixed to a test apparatus called a prober (not shown) by the use of a screw cramp. Moreover, the probe 12a is fixed to the substrate 11 in the neighborhood of the base by the use of a support member 15 composed of, for example, an organic material such as epoxy resin.
When the probe 12a is composed of tungsten, the probe 12a is designed so that the probe 12a is positioned to the center of a bonding pad at 85° C., and the probe 12a is used at a temperature near this temperature. At this time, when the length of the probe 12a is 20 mm, in a case where the operating temperature increases by 100° C., the length of the probe 12a increases by about 11 μm due to thermal expansion. Thus, the tip of the probe 12a is shifted in the direction of an arrow C to be moved off the center of a bonding pad. Moreover, when the length of the probe is 30 mm, in a case where the operating temperature is 25° C., the probe shrinks by about 8 μm or more. Even in this case, the tip of the probe is moved off the center of a bonding pad.
In this manner, in situations in which the chip size is decreased, and the size of a bonding pad is also decreased, a probe expands or shrinks due to a change in the test temperature. Especially, when the tip of a probe is shifted in the horizontal direction, the following problems occur: For example, the tip of a probe damages the top surface of a bonding pad, or a problem occurs in bonding because a probe trace overlaps with a bonding position used in actual chip bonding. Thus, there is a problem with an existing probe card such that the position of the tip of a probe needs to be optimized for each test temperature.